Among the most important selling features of automobiles is the quality of their painted finish. For this reason, nearly half of automobile assembly costs are devoted to coating operations. See generally, "Automobile Coatings: Helping Detroit Woo Consumers", Chemical Week, 30 (Jul. 4, 1984). As aerodynamic body styles become more prevalent, and sharp edges and other decorative detail features continue to be removed from automobile bodies, paint finish will exert an increasingly important influence on the overall decorative appearance of automobiles.
For these reasons, about 70% of the cars sold in the U.S. market are coated with a metallic finish. The difference in brightness and hue obtained when such a finish is observed emphasizes the styling lines of the car, highlighting small curvatures. This effect is known as "flop." The new base coat/clear coat paint finishes, which provide "wet look" paint finishes with or without a metallic appearance, can be used to produce a very high quality metallic finish with excellent flop, and are emerging as the finish of choice in the automobile industry. See, e.g., J. Schrantz, "Painting the Corvette", Industrial Finishing, 18 (March, 1984). In addition, because the clear coat protects the base coat, greater quantities of pigments can be incorporated into the base coat without the weatherability of the finish being unacceptably decreased. Base coat/clear coat finishes, however, and particularly metallic finishes, pose significant (and expensive) pollution problems arising from the evaporation of harmful paint solvents. Moreover, they are difficult to provide on plastic automobile body panels, which are becoming a popular mode of construction in the industry. Finally, base coat/clear coat paint finishes in general involve multiple painting steps which are very expensive to perform when high quality standards are maintained.
Accordingly, objects of the present invention are to provide a way to produce automobiles and the like with high quality decorative finishes like a base coat/clear coat finish, which can be used on molded plastic body panels, which does not require expensive painting steps, and which serves to reduce the emission control problems previously faced by manufacturers who wished to produce automobiles with base coat/clear coat finishes.